libfshelp: Support for file record locking

2019-03-03  Svante Signell <svante.signell@gmail.com>

	* rlock-tweak.c: Require write access for F_SETLK64 and
	  F_SETLKW64 according to POSIX-1003.1.

2019-02-12  Svante Signell <svante.signell@gmail.com>

	* rlock-tweak.c: Comment out check of lock->l_type and open_mode

2019-02-01  Svante Signell <svante.signell@gmail.com>

	* Update copyright years.
	* 2018-12-07:
	  - Fix typo in fshelp_rlock_tweak.
	  - Move description of rendezvous to fshelp.h.
	  - Removed 64bit versions

2018-12-07  Svante Signell <svante.signell@gmail.com>

	* Update copyright years.

	* rlock-tweak.c (fshelp_rlock_tweak): Add new argument:
	mach_port_t rendezvous.

2017-01-05  Svante Signell <svante.signell@gmail.com>

	* Update copyright years and headers.
	* rlock_tweak.c: l_pid is set to 0 when a conflicting lock
	is taken by another process. Will be fixed by new proc RPCs.

2016-05-23  Svante Signell <svante.signell@gmail.com>

	* rlock-drop-peropen.c: Port from cthreads to libpthread.
	* rlock-tweak.c: Likewise
	* fshelp.h: Likewise
	* rlock.h: Likewise

2001-04-12  Neal H Walfield  <neal@cs.uml.edu>

	* fshelp.h (struct rlock_box): New structure.
	(struct rlock_peropen): Likewise.
	(fshelp_rlock_init): New function.
	(fshelp_rlock_po_init): Likewise.
	(fshelp_rlock_drop_peropen): Likewise.
	(fshelp_rlock_tweak): Likewise.
	(fshelp_rlock_peropen_status): Likewise.
	(fshelp_rlock_node_status): Likewise.
	* rlock-drop-peropen.c: New file.  Implement
	fshelp_rlock_drop_peropen.
	* rlock-status.c: New file.  Implement
	fshelp_rlock_peropen_status and fshelp_rlock_node_status.
	* rlock-tweak.c: New file.  Implement fshelp_rlock_tweak.
	* rlock.h: New file.
	* extern-inline.c: New file.
	* Makefile (installhdrs): Add rlock.h.
	(SRCS): Add extern-inline.c, rlock-drop-peropen.c, rlock-tweak.c
	and rlock-status.c.

1 files changed, 53 insertions, 0 deletions

diff --git a/libfshelp/rlock-status.c b/libfshelp/rlock-status.c
new file mode 100644
index 00000000..718e540a
--- /dev/null
+++ b/libfshelp/rlock-status.c
@@ -0,0 +1,53 @@
+/* Copyright (C) 2001, 2014-2019 Free Software Foundation, Inc.
+
+   Written by Neal H Walfield <neal@cs.uml.edu>
+
+   This file is part of the GNU Hurd.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "fshelp.h"
+#include "rlock.h"
+#include <fcntl.h>
+#include <sys/file.h>
+
+int fshelp_rlock_peropen_status (struct rlock_peropen *po)
+{
+  struct rlock_list *l;
+
+  if (! *po->locks)
+    return LOCK_UN;
+
+  for (l = *po->locks; l; l = l->po.next)
+    if (l->type == F_WRLCK)
+      return LOCK_EX;
+
+  return LOCK_SH;
+}
+
+/* Like fshelp_rlock_peropen_status except for all users of NODE.  */
+int fshelp_rlock_node_status (struct rlock_box *box)
+{
+  struct rlock_list *l;
+
+  if (! box->locks)
+    return LOCK_UN;
+
+  for (l = box->locks; l; l = l->node.next)
+    if (l->type == F_WRLCK)
+      return LOCK_EX;
+
+  return LOCK_SH;
+}
+